The notorious Texas prison gang under investigation in the slayings of two North Texas prosecutors instills in its members the motto “God Forgives, Brothers Don’t.”

The Aryan Brotherhood of Texas, a white-supremacist gang formed in the 1980s, is known to flex its muscle with hits on rivals or its own members if they stray, with leaders assigning dirty work to prospects or lower-level members.

Now, law enforcement officers are investigating whether the ABT is behind the killings of Kaufman County District Attorney Mike McLelland and his wife, Cynthia, over the weekend and of one of McLelland’s prosecutors, Assistant District Attorney Mark Hasse, in January, according to media reports that cite Congressman Ted Poe, R-Humble, and law enforcement sources.

(Dai Sugano/San Jose Mercury News/MCT)

“I don’t envision the ABT bringing more heat on themselves by going around killing public officials,” said Terry Pelz, a former prison warden with the Texas Department of Criminal Justice who studies prison gangs. “That doesn’t mean they didn’t do it.”

The connection might be coincidental, though state police in December warned of potential retaliation in the wake of a Justice Department and Texas Department of Public Safety crackdown: a racketeering indictment in Houston that greatly disrupted the gang’s criminal activities.

Local, state and federal law enforcement officers arrested 34 of the gang’s members on charges including attempted murder and drug and illegal gun deals, including the killing near San Antonio in 2008 of Mark Davis Byrd Sr., who was kidnapped, beaten, stabbed and shot to death. By the time of the indictment in Houston, three ABT members had already pleaded guilty in San Antonio for their roles in Byrd’s killing.

Among the suspects indicted in November were current generals of the ABT, including one who is listed in media reports as a cooperating witness.

The indictment alleged that some racketeering acts occurred in Kaufman County and that some of the suspects were arrested or charged previously in that county, which is near Dallas.

Shortly after the crackdown, DPS issued a warning that the ABT could be planning retaliation against law enforcement officers who helped produce the indictment.

“High-ranking members … are involved in issuing orders to inflict ‘mass casualties or death’ to law enforcement officials who were involved in cases where Aryan Brotherhood of Texas (members) are facing life sentences or the death penalty,” the DPS bulletin said.

In its most recent gang threat assessment, DPS classified the ABT in “Tier 2” of its most significant gangs in Texas, behind “Tier 1” gangs such as the Tango Blast, Texas Syndicate and Texas Mexican Mafia. The tiers are based on the level of threat posed by the gangs.

“We have been tracking them and reported on the big indictment in November largely because the ABT is so incredibly violent: more than 100 killings since 2007 and about 10 kidnappings,” said Heidi Bierich, a spokeswoman for the Alabama-based Southern Poverty Law Center. “One of the techniques is that, whoever does the killing, is they demand a severed finger from the trophy. It’s a pretty gruesome crew.”

Attacks on public officials or prosecutors are rare, though at least two incidents involving the ABT prompted alarm at the Bexar County Courthouse, including a purported plot to kill state District Judge Angus McGinty this year and a threat to Bexar County Assistant District Attorney Nicole Thornbro in 2008.

“In the past, the ABT was primarily concerned with the protection of white inmates and white supremacy/separatism,” federal investigators wrote in a report used during a prosecution of ABT members in San Antonio between 2010 and 2012. “Over time, the ABT has expanded its focus more towards a criminal enterprise to include illegal activities for profit.”

The group has its own constitution and maintains a paramilitary structure, with members reporting to generals, captains and lieutenants, and territory is divided according to how TDCJ splits its regions, records show.

Its primary criminal endeavors are methamphetamines, identity theft and prostitution, though it has made forays into other crimes and expanded its reach. It uses wives and girlfriends to deliver messages. Some of them are being prosecuted in the Houston case on charges that they aided in the racketeering.

Investigators estimate the gang’s numbers are around 2,600. Pelz, the former warden, said he’s seen numbers as high as 100,000, but he believes those numbers are overstated. He estimated the ABT’s confirmed members in Texas prisons at between 600 and 1,000, with others listed as associates or prospects.

“Aryan Brotherhood of Texas’ ranking within Tier 2 has increased,” DPS said in its 2012 gang threat assessment. “This change is due to several factors, including the gang’s large membership numbers and consistent level of violence and other criminal activity. Some information regarding the gang’s relationship with (Mexican drug) cartels continues to be reported.”

Members are required to sign a “blind faith commitment” in which they agree to do anything directed or requested by their superiors without question. Failure to comply might result in severe beatings or death.

The indictment said the organization maintains order and discipline through killings, threats of killings and other violence.

Still, most of its members live the philosophy of “14/88,” one investigation report shows. And members tattoo themselves with neo-Nazi symbols. The report said 14 represents the “Fourteen Words” that form the basis of their beliefs: “We must secure the existence of our people and a future for white children.”

The “8” represents the eighth letter of the alphabet (H), and when it appears twice, as “88,” or HH, it signifies “Heil Hitler.”

In ABT cases in the San Antonio area, the gang’s viciousness has been highlighted.

In October 2008, James Lamy, 37, of Converse was shot once in the back and once in the chest before his head and hands were cut off, apparently in an effort to conceal the identity of the corpse. A month later, authorities found what they believed to be the partly burned remains of Lamy’s head and hands.

William “Kowboy” Knittel, a reputed ABT member, was charged with Lamy’s killing by Kendall County prosecutors, who later dismissed the case when Knittel was indicted on a federal gun charge in Oklahoma, records show.

Byrd, the man killed near San Antonio in 2008, was believed to have kept drugs he was supposed to deliver on behalf of the gang. He was kidnapped by Houston-area members of the ABT. Byrd was tortured, beaten, stabbed repeatedly and shot by each of his three to four attackers, court records show.